A drug that stops tumours developing resistance to chemotherapy is to be tested on patients with two of most deadly cancers.

Scientists have shown that the compound, known as CCT245737, boosts the effectiveness of cancer treatment in mice.

They are now preparing to give it to trial patients suffering from lung and pancreatic cancers, both diseases with poor survival rates.

The drug belongs to a new class of therapeutic agents called CHK1 inhibitors, which can be delivered orally as a pill or liquid that is swallowed rather than injected.

It targets a molecule called CHK1 that cancer cells activate to help them repair the DNA damage inflicted by chemotherapy.

The hope is that blocking the molecule will prevent cancers becoming resistant and improve the effectiveness of chemotherapy drugs.

Professor Ian Collins, from the Institute of Cancer Research (ICR) in London, where CCT245737 was discovered, said: " We're excited that our new CHK1 inhibitor... is progressing towards first-in-human clinical trials.

"By using CHK1 inhibitors with chemotherapy, we block one of cancer's escape routes and prevent tumours from evading the effects of treatment. We hope that clinical trials of our new drug will show it to be an effective chemotherapy booster in lung and pancreatic cancers, which readily become resistant to current treatments."

Research published in the journal Oncotarget showed that the drug strongly suppressed CHK1 in human cancer cell lines.

In mice with human tumours, it greatly increased the ability of chemotherapy to kill cancer without worsening side effects.

The scientists are now working with Cambridge drug discovery company Sareum to take CCT245737 into early-stage clinical trials.

Financial support is also being provided by Cancer Research Technology (CRT), a subsidiary of leading charity Cancer Research UK, through the CRT Pioneer Fund (CPF).

Dr Phil L'Huillier, CRT's director of business development, said: "The CRT Pioneer Fund was set up to help bridge the funding gap between the lab and the clinic and we're delighted that this investment from CPF and Sareum means a promising molecule is now ready for clinical trials.

"Lung and pancreatic cancers have some of the lowest survival rates of any cancer type, so we hope this vital injection of cash and resources will mean patients can benefit from this research sooner."